How to check a construction subcontractor's references

A subcontractor can list impressive projects without showing what its own team actually did. A reference check helps a buyer test whether previous work is comparable to the proposed package and how the firm handled changes, coordination and problems. It should be a structured conversation, not a popularity vote or a substitute for checking current insurance, competence and site arrangements.

HSE's Managing contractors guidance includes references among information a buyer may ask for when choosing a contractor. Its Using contractors guidance says the degree of competence and supporting evidence depends on the job. Ask fewer but more relevant questions for a simple task, and deeper ones when the work involves significant hazards or coordination.

Choose a comparable reference

Before calling, write down the proposed trade, scope, size, location, programme constraints and any specialist risk. Ask the supplier for a recent project where it performed similar work under a similar role. A firm that supplied labour on a large project has not necessarily managed the design or acted as principal contractor. If a parent company or previous employer delivered the cited job, clarify the connection to the bidding entity and named supervisors.

Ask the reference contact what role they held and how directly they observed the work. A project manager who saw daily coordination can speak to different facts from a purchasing contact who only saw invoices. Record permission to contact the referee and keep their comments within your procurement process. Do not circulate personal details more widely than necessary.

Ask questions that test delivery

Use a consistent core set, then add questions for the package:

1. What work did this legal entity perform, and when?
2. Which parts did it self-perform, and which did it subcontract?
3. Who supervised the work, and were those people from the same team now proposed?
4. How did it plan and coordinate its work with other trades or an occupied site?
5. Were there material safety, quality or programme issues? How were they reported and resolved?
6. Did its method change when the scope, design or site conditions changed?
7. Which aspect of the proposed new package would be outside the experience you observed?
8. Would you consider the firm for a similar scope again, and why?

These are sample procurement questions, not questions prescribed by HSE. Avoid eliciting confidential contract details, unsupported allegations or sensitive personal information. If a referee cannot answer something, record “not known”, not a guessed positive or negative.

Verify the account, then make a bounded decision

Compare the reference with the supplier's submitted project description: dates, entity, trade, role and magnitude of work. If details do not align, ask the supplier for an explanation and check another source where proportionate. A discrepancy may be a benign change of trading name or a real capability concern; do not assume either without evidence.

Record three things separately: facts confirmed, questions still open, and the conclusion for this specific package. A positive reference can support an experience assessment. It does not prove the current workforce has the necessary qualifications, that insurance covers the new job, or that the supplier's RAMS fits the site. HSE's contractor guidance keeps selection, risk assessment, information and coordination as related but distinct activities.

If a reference identifies a serious incident or poor performance, avoid an automatic unreviewed rejection. Ask what happened, what was within the supplier's control and what corrective action it took. Escalate a material concern to the authorised procurement and safety reviewers. Apply the same criterion to comparable bidders and keep the decision reason.

Maintain a short reference record

Keep the project, referee role, contact date, questions, responses, evidence gaps, reviewer and decision. Note whether the reference is useful for future similar packages and when it becomes too old to rely on. For a later project with different risks, revisit the capability question rather than reusing a blanket “approved” status.

For the wider evidence list, use the subcontractor prequalification checklist. For the work-package evidence decision, use the document requirements matrix. When evaluating contractor prequalification software, ask whether it can retain the reference record and reviewer decision against the right supplier and package. Ask for a demonstration; this article makes no claim that Complys contacts referees, scores them automatically or validates their statements.

Primary sources and publication gate

• HSE — Managing contractors, HSG159: proportionate contractor selection and references among possible evidence.
• HSE — Using contractors, INDG368: define the job, assess suitability and coordinate work.

Before integration: Compare the whole live prequalification checklist and any owner page that already contains a full reference-checking workflow. If one already satisfies this exact query, merge these questions there rather than create a competing page. Keep the reference questions as editorial advice, not a claim of statutory wording.